Dental screwdriver

ABSTRACT

A shaft for a dental screwdriver configured to be inserted into a bore cavity of a dental prosthetic. The shaft has a drive tip for driving a dental screw used to fix the dental prosthetic to the dental implant when the shaft is inserted into the bore cavity of the dental prosthetic. The drive tip is made of a shape memory smart alloy. The shaft also has an axial shaft portion made of a shape memory smart alloy with different material characteristics than the shape memory smart alloy of the drive tip. The axial shaft portion is configured to elastically bend from an original shape to a bent shape along the axial shaft portion without imparting a bending action and torqueing forces along the drive tip when the dental screwdriver is inserted into the bore cavity of the dental prosthetic.

RELATED APPLICATIONS

The present application claims priority to related U.S. Non-Provisionalapplication Ser. No. 15/246,210, filed Aug. 24, 2016, which claimspriority to related U.S. Provisional Application No. 62/210,346, filedon Aug. 26, 2015, commonly owned and assigned herewith.

FIELD

The present disclosure relates to bendable screwdrivers, and inparticular, to bendable screwdrivers for use in dentistry for securingscrew-retained restorations and like-sized components.

BACKGROUND

A dental implant (also known as an endosseous implant or fixture) is asurgical component that interfaces with the bone of the jaw or skull tosupport a dental prosthesis such as a crown, bridge, denture, facialprosthesis or to act as an orthodontic anchor. The basis for modemdental implants is a biologic process called osseointegration wherematerials, such as titanium, form an intimate bond to bone. A variableamount of healing time is required for osseointegration before thedental prosthetic (a single crown, bridge or denture) is attached to theimplant. Alternatively, the dental prosthetic can be immediatelyattached to the implant before osseointegration has occurred foraesthetic and/or functional reasons.

Planning the position and number of implants is key to the long-termhealth of the prosthetic since biomechanical forces created duringchewing can be significant. The position of implants is determined inlarge part by the position and angle of adjacent teeth.

The final prosthetic can be either fixed, where a person cannot removethe denture or teeth from their mouth or removable, where they canremove the prosthetic. In each case an abutment is necessary whichcouples the dental prosthetic to the implant.

The risks and complications related to implant therapy are divided intothose that occur during surgery (such as excessive bleeding or nerveinjury), those that occur in the first six months (such as infection andfailure to osseointegrate) and those that occur long-term (such asperi-implantitis and mechanical failures). In the presence of healthytissues, a well-integrated implant with appropriate biomechanical loadscan have long term success rates of 93 to 98 percent for the fixture and10 to 15 year lifespans for the prosthetic teeth.

The securing of screw-retained restorations is usually performed usingappropriately sized and fitted screwdrivers. A screw-retained fixationis very often positioned at an angle in relation to the restoration'santerior plane.

Restorations having a non-straight or even a bended screw channel notonly allow flexibility in designing screw retained crowns, bridgesand/or dentures, they also eliminate the need for cementingrestorations.

FIG. 1 is a cross-sectional view 10 of a conventional cemented typerestoration. In a cemented type restoration, a dental implant 11 isfirst osseointegrated in the jaw portion 12 of a patient's mouth andthen a traditional prosthetic abutment 15 is threadedly secured into theimplant. Once the abutment is secured in position, the implantspecialist cements the prosthetic over the abutment as shown.

The alternate, screw retained approach 20 is best shown and illustratedin FIGS. 2A and 2B. In this approach, the abutment is integral with theartificial crown, bridge or denture that's fitted into the patient.Instead of first inserting an abutment and then cementing a crown overthe abutment, as for example is shown in FIG. 1 , here the dentalprosthetic (and integrated abutment) is positioned into the implant andsecured using a screw. The prosthetic is provided with cavity thatextends axially from an opening on the enameled surface of theprosthetic into and across the integrated abutment terminating into theimplant's co-axial threaded cavity. To secure the prosthetic into theimplant using a screw, the prosthetic cavity is sized to fit the screwand also the screwdriver shaft which must be able to reach and securethe screw to the implant.

In FIG. 2A, the restoration is shown just before the screw is insertedand secured.

In FIG. 2B, a screwdriver is shown extending into the prosthetic cavitywith intent to reach the screw (not shown) used to threadedly secure theprosthetic from the implant. In a similar manner, the prosthetic can beremoved by unscrewing the screw.

The screwdriver typically used with screw-retainer restorations arescrewdrivers with non-bendable shafts. The tips of commerciallyavailable screwdrivers are sized to accommodate design specifications ofone or more specific implant vendors.

Screwdrivers and screwdrivers tips come in varying sizes and shapesdepending on the specifications and screw types called for by therestoration's manufacturer. Very often, different manufacturersintentionally size restorations to force practitioners to purchase aspecific set of tools (including screwdrivers) which works in favor ofthe restoration manufacturers since practitioners are less likely toswitch to a different manufacturer if doing so may require buying a newset of tools. With that said, over time, tools have been introduced withinterchangeable heads and tips to address this problem.

Despite the overall benefits of such screw-retained restorations, thereremain significant manufacturing and aesthetic limitations involved increating a suitable restoration. This is partly attributed to the factthat in cases where the implant axis is going through the anterior planeof the restoration-prosthesis and due to the fact that the traditionaldental screwdrivers do not allow any angulation during the securing(screwing) of the restoration, the screw channel must end buccallyresulting in a less aesthetically satisfactory restoration.

One design approach for securing angled screw-retained restorations andimplant abutments in particular is described in international patentapplication WO2011080141, filed on Dec. 16, 2010 and assigned toStraumann Holding AG (hereafter “Straumann”) entitled “FLEXIBLE DENTALSCREWDRIVER AND METHOD OF MANUFACTURING THE SAME”.

FIGS. 3A-3C are different perspective views of a prior art Straumannscrewdriver 55. The Straumann screwdriver 55 is capable of bending alongthe shaft region by virtue of a multitude of cylindrically shaped hollowshaft segments 60 that combine to form a flexible shaft 65. The flexibleshaft segments interlock to provide limited movement in any directionalong the shaft, substantially as shown in accompanying FIG. 3A.

FIGS. 3B and 3C are blown up, top level diagrammatic view andcross-sectional views, respectively, showing a single shaft segment 60.Due to the interlocking nature of segments 60 along shaft 65, a torqueapplied to shaft 65 from a handle portion 70 is transferred to aconnected or integral drive tip 75. The dimensions of screwdriver 55,including size and number of shaft segments, depend on the amount oftorque and desired range of curvature desired. In practice, however, thesegmented nature of the Straumann design makes it impractical for allbut the easiest-to-access restorations. The shaft is difficult to cleanand costly to manufacture; difficult to apply even torque pressure alongthe vertical axis of the screw in many instances; and otherinefficiencies.

A more recent approach in dealing with angled screwed restorations hasbeen recently proposed by Nobel Biocare which employ a unique screw headwhich it calls an Omnigrip™ Interface design.

FIGS. 4A-4I illustrate the prior art Omnigrip approach.

Referring to FIG. 4A, this is a partial perspective view of a patient'smouth. One tooth is very clearly a screw-retained type restoration 405,given the presence of a bore cavity 406 which is shown in ghost view.

A cross-sectional view of restoration 405 is shown in FIG. 4B. Here, wesee very clearly the presence of a dental prosthetic 410 fixed by asscrew (not shown) threaded along a planar axis to a dental implant 420.An appropriate set of abutments connecting dental prosthetic 410 todental implant 420, similar to the restoration shown in FIGS. 2A and 2B,while not shown may be presumed. The purpose of bore cavity 406 is tofacilitate feeding a screwdriver into the open cavity to allow fixedlysecuring the appropriate screw.

In the configuration shown in FIG. 4B, dental prosthetic 410 is designedto be screwed at angle of 0 degrees off axis from the abutment face.Obviously, this has the negative result of providing ingress to cavity406 from the front of the dental prosthetic. This means once theprosthetic is secured in place, the dental practitioner must fill thehole of the prosthetic (crown) to achieve a desired tooth-like aestheticlook and feel. This is not always easy or possible to achieve when abore cavity is large.

An alternative approach to fix a dental prosthetic is to provide thebore cavity through which the screw will be secured at an angular leveloff axis. This way the opening of the bore cavity is not visible fromthe front. All the filling is done anteriorly.

An example cross-sectional view of a restoration 425 with a dentalprosthetic 432 having an associated bore cavity positioned at an offsetof 25 degrees off the planar axis of dental implant 433 is shown in FIG.4C.

Referring to FIGS. 4D-4F, we see that for the restoration of FIG. 4D, aspecially designed screw 435, screwdriver 440, and screwdriver tipinterface 445 must be provided to facilitate angular torqueing (450) ofscrew 435 along the 25 degree axis off the anterior plane of dentalimplant 433 in the illustrated example.

For greater accuracy in providing proper torqueing to an optimal finalsetting, a torque adjusting tool 460 may be coupled to the screwdriverhandle. An example of this is shown in shown in FIGS. 4H and 4I.

To allow the non-bendable type screwdriver 440, as shown, to reach thescrew in order to fixedly secure dental prosthetic 432 into dentalimplant 433, it is necessary that the opening associated with borecavity be large enough to permit positioning screwdriver therein at anangle. Often this is only possible if bore cavity is partially open orexposed.

The use of a Straumann type screwdriver very clearly is not suitable fora number of reasons. For one, it is not believed possible to guaranteethat the Straumann screwdriver will apply the twisting forces impartedon the Straumann handle so as to generate the desired torqueing forceson the head of the screw in the same manner and to the same extent as anon-bendable screwdriver. Any off-planar axis, or like uneven forces,could result in improper threading and possible destruction of thedental implant, the dental prosthetic, the screw, associated abutments,or a combination of the above.

In addition, it is not believed possible to design a suitable Straumannscrewdriver that will bend along its tip in an optimal manner so as toimpart a perfectly vertical pushing force on the screw during threading.

Additionally, it is not clear that the Straumann screwdriver may be usedwith accuracy when employing a torque adjusting tool.

Regarding the Omnigrip approach, in addition to the need for anon-bendable screwdriver, as described above, it also suffers from anumber of drawbacks which makes its use by practitioners difficult,costly, and inflexible in terms of being able to use the drive tips forother dental related functions, applications and/or with differentmanufacturer screw heads/tips.

There is a need therefore for an improved screwdriver design that is lowcost, easy to use, efficient, flexible, versatile, robust, morehygiene-friendly, capable of preventing the incidence ofperi-implantitis resulting from improper screwing, mechanically failproof, and at the same time manufacturer tip- and screw-head agnostic.

SUMMARY

The present disclosure relates to a dental screwdriver having a shaftportion made of a smart type alloy that bends with little or noresistance along an arch forming portion thereof and without impartingtorqueing forces along a distal front end portion thereof onto which isconnected a drive tip designed to interface with an appropriately sizedscrew. The smart alloy automatically assumes its original shape in theabsence of bending forces on the shaft along the arch forming portion.In an alternate embodiment, assuming the original shape involvesapplying heat and/or subtle finger pressure.

In accordance with a further exemplary embodiment, the dentalscrewdriver is part of a set of screwdrivers, each having a distal frontend portion which is uniquely weighted, sized and/or dimensioned toaccommodate different driver tips, handle different torqueing functions,and/or configured to bend to a specific maximum angular arch withoutpermanent deformation. The screwdrivers may be uniquely identified(e.g., color coded) to identify the screwdriver's design specifications,such as elasticity type parameters.

In another embodiment, the set of screwdrivers are designed to haveintegral tips to accommodate different manufacturer screw heads.

In another embodiment, the shaft includes a second distal end, oppositethe distal front end portion gripping end of the shaft, configured tocouple to a handle portion, or to a torque measuring tool. The handleportion itself may also be designed to work with a conventional torquemeasuring tool.

In another embodiment, the smart alloy is sized and or made of smartalloy material along just that portion of the shaft intended to receivethe optimum bending forces without imparting any bending action or forcealong the distal front end portion, which distal front end portion ismade of either a non-smart alloy material, or of a smart alloy materialof different type.

In yet another embodiment, the drive tips are sized with diameters lessthan or equal to 0.4 mm resulting in smaller vents (cavities) in thecrown which results in increased overall strength of the restoration.

In a preferred embodiment, the smart alloy is Nickel titanium.

In an example scenario, the dental screwdriver is characterized by veryhigh elasticity. Exposing the screwdriver to heating and/or applyingsubtle finger pressure helps with recovery to an original shape prior tobending. As such, the dental screwdriver is able to achieve a very highkink-resistance in concert with the ability to bend through torturouspaths without experiencing strain localization and/or plasticdeformation.

In yet another embodiment, the dental screwdriver has a very narrowdesign profile and sized to couple to an elastic abutment extractor oractivator for Morse taper implant designs. This allows removing anabutment immediately after screw removal or, alternatively, to tightenan abutment without the use of a screw.

In yet another embodiment, the dental screwdriver is sized to have avery long shaft for flexibility in hard to reach places. The same shaftmay alternatively include a telescopic portion disposed along anon-bendable, non-elastic portion of the shaft for even greaterflexibility in use.

In yet a further embodiment, at least one of the shaft and the distalfront end portion are magnetized to magnetically grip either a drivertip, the screw to be inserted, or both.

In yet a further embodiment there is further provided screws made ofsimilar smart alloy material designed to conform to the specific shapeof a vent or screw cavity when positioned for screwing to take advantageof the greater flexibility and reach the dental screwdriver proposedherein.

In yet a further embodiment, an electronic platform or stand-alonesoftware tool is provided to facilitate in the training or appropriateselection of a screwdriver having an elasticity, size, and/or dimensionmatching a restoration's optimum design specifications.

In another aspect, a screw-retained type dental prosthetic is providedhaving a curved bore cavity configured to facilitate the use of abendable screwdriver. The dental prosthetic includes an artificial toothportion coupled to a prosthetic abutment. The curved bore cavity extendsfrom an opening in the artificial tooth portion to an opening in theprosthetic abutment. The bendable screwdriver is a screwdriver of thetype having a shaft made of a smart alloy with shape memory andsuperelasticity.

A method is also disclosed which involves identifying a screw type to beused to secure a dental prosthetic to a dental implant. At least one ofa bendable screwdriver having a smart alloy shaft with integral drivetip end, a smart alloy shaft with integral drive tip end, and a drivetip end of the type configured to connect to a smart alloy shaft, areselected from a set of a plurality of same, respectively, on the basisof the screw type identified.

These and other features and advantages of the present invention will beapparent from the description of exemplary embodiments provided herein.

These and other features and advantages of the present invention will beapparent from the description of exemplary embodiments provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Purposes and advantages of the exemplary embodiments will be apparent tothose of ordinary skill in the art from the following detaileddescription in conjunction with the appended drawings in which likereference characters are used to indicate like elements, and in which:

FIG. 1 is a cross-sectional view 10 of a dental implant 11osseointegrated in jaw portion of a patient's mouth, and having a dentalprosthetic shown fixed to dental implant using dental cement.

FIGS. 2A and 2B illustrate in cross-sectional view, a conventionalscrew-retained restoration approach, before screwing and duringscrewing, respectively.

FIGS. 3A-3C are different perspective views of a prior art Straumannscrewdriver.

FIGS. 4A-4I illustrate the prior art Omnigrip approach.

FIG. 5 is an example dental screwdriver in accordance with an exemplaryembodiment with integral tip(s).

FIG. 6 is a graphical illustration of superelastic bending behavior ofthe proposed dental screwdriver manufactured from smart alloy material.

FIG. 7 shows an alternately shaped, smart alloy shaft in accordance withyet another exemplary embodiment.

FIG. 8 shows a cross-sectional view of a screw-retained type restorationconfigured to be secured via a bore cavity that is at least partiallycurved.

FIG. 9 shows a cross-sectional view which is a closer look of the screwretained type restoration in FIG. 8 with a bendable screwdriver shaftplaced in the bore cavity during screw tightening action.

DETAILED DESCRIPTION

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments.

The following description is intended to convey a thorough understandingof the embodiments described by providing a number of specificembodiments and details involving methods and systems for managingcontent submission and publication of content. It should be appreciated,however, that the present invention is not limited to these specificembodiments and details, which are exemplary only. It is furtherunderstood that one possessing ordinary skill in the art, in light ofknown systems and methods, would appreciate the use of the invention forits intended purposes and benefits in any number of alternativeembodiments, depending upon specific design.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to limit the scope of the presentinvention. As used throughout this disclosure, the singular forms “a,”“an,” and “the” include plural reference unless the context clearlydictates otherwise. Thus, for example, a reference to “a module”includes a plurality of such modules, as well as a single module, andequivalents thereof known to those skilled in the art.

The present disclosure relates to a dental screwdriver having a shaftportion made of a smart type alloy that bends with little or noresistance along an arch forming portion thereof and without impartingtorqueing forces along a distal front end portion thereof onto which isconnected a drive tip designed to interface with an appropriately sizedscrew. The smart alloy automatically conforms to its original shape uponremoval of the twisting forces on the shaft along the arch formingportion which caused the arching in the first place.

In an alternate embodiment, assuming the original shape involvesapplying heat and/or subtle finger pressure.

In accordance with a further exemplary embodiment, the dentalscrewdriver is part of a set of screwdrivers, each having a distal frontend portion which is uniquely weighted, sized and/or dimensioned toaccommodate different driver tips, handle different torqueing functions,and/or configured to bend to a specific maximum angular arch withoutpermanent deformation. The screwdrivers may be uniquely identified(e.g., color coded) to identify the screwdriver's design specifications,such as elasticity type parameters.

In another embodiment, the set of screwdrivers are designed to haveintegral tips to accommodate different manufacturer screw heads.

An example dental screwdriver 505 in accordance with an exemplaryembodiment with integral tip(s) is shown in FIG. 5 . The screwdriver 505includes a handle portion 510 and a shaft 520 and is designed to coupleto any conventional torque measuring tool 515. As can be seen, a shaft520 may be provided with any number of different integral driver tips(shown as shaft portions 520 a-520 g). Each of shaft portions 520 a-520g are integrally formed and extend downwardly from a topmost shaftportion 520′. Shaft portions 520 a-520 g are a few examples of differentintegrated screwdriver tips with which shaft 520 may bedesigned/provided.

Screwdriver 505 may be marketed and sold as a stand-alone integral shaftmade of a smart alloy material and provided with a specific driver tip,such as anyone of the driver tip options 520 a-520 g (collectively 530)shown in FIG. 5 . Screwdriver 505 may also be marketed as a set ofscrewdrivers, each screwdriver being provided with a specific type oftip substantially as shown. One skilled in the art would appreciate thatthere are many different tips and the decision to market a set ofscrewdrivers with more or fewer tips is a commercial decision.

Shaft 520, in accordance with an exemplary embodiment, includes a latchend 535 designed to mate and fixedly secure the shaft to handle portion510, or directly to a torque measuring tool depending one type ofmechanism design one chooses to employ.

The key aspect is the shaft construction and design. The shaft 520 mayrecover its shape after bending due to the use of smart alloy typematerial. Shape recovery may be automatic (e.g., no heating,electricity, or magnetism is applied). In another scenario, the recoveryis assisted in that a minimum amount of finger pressure or some form ofheat is involved for the smart alloy shaft to fully return to a non-bentposition.

In a preferred embodiment, the smart alloy is Nickel titanium, alsoknown as nitinol. Nitinol is a metal alloy of nickel and titanium, wherethe two elements are present in roughly equal atomic percentages e.g.Nitinol 55, Nitinol 60. Nitinol alloys exhibit two closely related andunique properties: shape memory and superelasticity.

Shape memory is the ability of nitinol to undergo deformation at onetemperature, then recover its original, undeformed shape upon heatingabove its “transformation temperature”. Superelasticity occurs at anarrow temperature range just above its transformation temperature. Inthe scenario where the shaft exhibits “superelasticity”, no heating maybe necessary to cause the undeformed shape to recover. The uniqueness ofusing a material like Nitinol is that it can, under certain uses,possess both shape memory and superelasticity. In uses where completesuperelasticity is either not possible or not desirable, applying heator some gentle finger pressure to assist with recovery into an unbentposition may be necessary or desirable.

Applicants tap the special nature of Nitinol to construct a dentalscrewdriver which for the first time aims to allow dental practitionersto fit a screwdriver through closed bore cavity spaces, both curved andstraight, through which the smart alloy shaft end will travel to reach ascrew used to secure a dental prosthetic to a dental implant.

Due to the nature of the shaft being bendable, except at or near thepoint of impact between the shaft end and the screw, the twisting forcesapplied by the practitioner are evenly and uniformly transferred throughthe shaft as if the screwdriver shaft were a non-bendable type shaft.

In accordance with an exemplary embodiment, the smart alloy is sized andor made of smart alloy material along just that portion of the shaftintended to exhibit an optimum bending characteristic (elasticity)without imparting any bending action or force along the portion 520′ ofshaft 520 which extends from latch end 535.

In one scenario, portion 520′ is made of either a non-smart alloymaterial, or of a smart alloy material of different elasticity, or ofthe same smart alloy but with different elasticity attributes along theshaft length to achieve desired bendability consistent with the intendedaction to be taken.

In yet another embodiment, the drive tips are sized with diameters lessthan or equal to 0.4 mm resulting in smaller vents (cavities) in thecrown which results in increased overall strength of the restoration.

In yet a further embodiment, it is contemplated that the ability, forthe first time, to be able to provide an accurate bendable screwdriverwith tip ends that can fit along a curved bore cavity in a dentalprosthetic which extends to a prosthetic abutment designed to receive ascrew, gives rise to new type dental prosthetic devices (crowns,bridges, and the like) which may be constructed with curved borecavities and designed to work with bendable, smart alloy shafted dentalscrewdrivers, as proposed herein.

A graphical illustration of superelastic bending behavior of theproposed dental screwdriver manufactured with smart alloy material(preferably nitinol) is illustrated in FIG. 6 .

Here we see shaft 520 bent to different angles. Latch end 535 and shaftportion 520′ do not bend at all. By contrast, the smart alloyed portionof shaft 520 is designed to flexibly bend to different angles and withdifferent degree of curvature depending on the bending force applied, asshown. In positon A, shaft 520 is shown in a natural state (non-bent)position. In position B, we see shaft 520 bent at approximately 25degrees off normal state (position A). In position C, the bent angle isapproximately 55 degrees. In the accompanying parallel figure we see thesame shaft 520, this time in a position D, with a bent angle near or at90 degrees off normal. For each bent angle, we see that shaft 520 beginsto bend at different positions depending at the angle of incidence atwhich the torqueing force will be applied. At position D, we see that atorqueing force is to be applied to a dental prosthetic 600 (shown inpartial cross-sectional view).

Dental prosthetic 600 includes an artificial tooth portion 610 intowhich has been fitted a conventional type screw retained type prostheticabutment 620. Prosthetic abutment 620 includes a bore cavity 630(preferably non-curved) configured to receive the screw (not shown)that's intended to secure dental prosthetic 600 to an abutting dentalimplant (not shown) for which it is designed, in the manner previouslydescribed above in connection with FIGS. 2A and 2B.

The artificial tooth portion 610 is unique in that it includes a“curved” bore cavity 640 which runs from the internal bore cavity 630 ofabutment 620 to an eventual opening at the screw insertion end of dentalprosthetic 600. While it is not necessary for bore cavity 640 to becurved, a curve may be desirable to allow the practitioner to screwdental prosthetic 600 to a dental implant for those teeth whereadditional bending elasticity is needed or desired to access duringscrewing and/or when, due to the nature of the tooth, it is easier toachieve a more aesthetic final result when filling in bore cavity 640 tocomplete the restoration.

The desired goal, again, is to provide a shaft capable of bending in anarch like manner along a central portion thereof but capable ofmaintaining a substantially linear curvature near and along the drivetip end portion 550 to allow coupling same to a screw to be fitted in anabutment.

In an example scenario, the dental screwdriver is characterized by veryhigh elasticity. Exposing the screwdriver to heating and/or applyingsubtle finger pressure helps with recovery to an original shape prior tobending. As such, the dental screwdriver is able to achieve a very highkink-resistance in concert with the ability to bend through torturouspaths without experiencing strain localization and/or plasticdeformation.

FIG. 7 shows alternately shaped, smart alloy shafts in accordance withyet another exemplary embodiment. Shaft 710 is designed to function asan extractor tool in a Morse taper implant type configuration, whileshaft 720 can be used as the activator tool to “activate” a Morse taperimplant configuration.

Shaft 710 is characterized by a smart alloy distal end portion 710′which consists of a threaded portion 711 and a non-threaded portion 712.Portion 710′ is a conventional extractor tool end design with the onlydifference being that distal end portion 710′ is configured so as tobend into position during extraction, in the same way as has beendescribed above in connection with the bendable screwdriverconfigurations. While Morse taper designs comprise both screw- andnon-screw type implementations, the extractor tool itself provides theunlocking force needed to disengage (unlock) a prosthetic Morse taperedabutment (not shown) from the associated dental prosthetic.

Shaft 720, as explained, helps with activating the locking of theabutment to the prosthetic in a Morse taper design and also includes asmart alloy distal end portion 720′, which in turn consists of athreaded portion 721 and a non-threaded portion 722 (with threadedportion 721 located at the complete distal end of shaft 720). Portion720′ is likewise a conventional activator tool end design with the onlydifference again being that distal end portion 720′ is configured so asto bend into position during activation, in the same way as has beendescribed above in connection with the bendable screwdriverconfigurations.

Technically speaking, smart alloy activator and extractor type shafts720, 710 operate to couple and decouple, respectively, a Morse taperabutment to a fitted design dental prosthetic, and in this regard behaveas dental screwdrivers as contemplated and defined herein. In the caseof a Morse taper design of the type incorporating a screw in addition to(or as part of) the locking mechanism of the Morse taper configureddesign, shafts 710, 720 are designed to simultaneously impart thenecessary torqueing of the available screw at the time of activation ofthe locking mechanism. If there is no screw, then the purpose of dentalscrewdriver with a shaft 720 is to engage the locking mechanism in theMorse taper configured implant alone. Likewise, the purpose of a dentalscrewdriver with a shaft 710 is to disengage the locking mechanism.

FIG. 8 shows a cross-sectional view of a screw-retained type restoration800 configured to be secured via a bore cavity 810 that is at leastpartially curved to allow a bendable screwdriver (not shown) with theproposed design to be inserted and the right amount of torque applied tothe screw.

FIG. 9 shows a cross-sectional view which is a closer look ofrestoration 800—with a bendable screwdriver shaft 820 in position duringscrew tightening action. While the screwdriver axis at the point ofinsertion of the screw may appear bent, it is preferred that the vent besized so that at the point where torque is applied the only forceexerted on the screw at the point of contact is a radial (or torqueingtype) force.

The screwdriver shaft and/or accompanying drive tips may be configuredto match multiple restoration type specifications for added flexibility.Latch end 825 may be sized to have a universal head to accommodatedifferent size or type handles, as well as torque-calibration andmeasuring type devices.

In yet another embodiment, the dental screwdriver is sized to have avery long shaft for flexibility in hard to reach places. The same shaftmay alternatively include a telescopic portion disposed along anon-bendable, non-elastic portion of the shaft for even greaterflexibility in use.

In yet a further embodiment, at least one of the shaft and the distalfront end portion are magnetized to magnetically grip either a drivertip, the screw to be inserted, or both.

In yet a further embodiment there is further provided screws made ofsimilar smart alloy material designed to conform to the specific shapeof a vent or screw cavity when positioned for screwing to take advantageof the greater flexibility and reach the dental screwdriver proposedherein.

In yet a further embodiment, an electronic platform or stand-alonesoftware tool may be provided to facilitate in the training orappropriate selection of a screwdriver having an elasticity, size,and/or dimension matching a restoration's optimum design specifications.

In one scenario, the platform is a smart-phone application providingappropriate visuals to help the practitioner select the appropriatetool, order replacement tips, learn about specific manufacturertorqueing specifications, and the like.

In yet a further embodiment, an electronic platform or stand-alonesoftware tool, such as a smart phone application, may be provided to aidthe practitioner in choosing an appropriately sized dental prosthetic ofthe type having a curved bore cavity to achieve an optimum aestheticresult and/or to achieve an optimum use of a bendable smart alloyedscrewdriver during torqueing.

It should be appreciated that the use of a solid material instead of asegmented shafted design of Straumann or like prior art designs preventshaving plural perpendicular forces applied on the abutment with at leastone having a horizontal force vector capable of causing dislocation orfracture of an abutment.

By eliminating multiple non-angular forces, the torqueing force that isintentionally imparted by the practitioner is the only force beingimparted on the screw head resulting in an optimum securing of a screwin position. At the same time, the level of skill and attention requiredby the practitioner is significantly reduced as are the risks of over-or under-torqueing and/or wrong torqueing, by the practitioner.

Because the shaft is not segmented, bending along different portions ofthe shaft is prevented. Uniform force distribution prevents futuremechanical related fractures.

The proposed screwdriver provides improved resistance to repetitivestrain excursions due to the homogenous material used.

Likewise, the improved shaft design results in bend uniformity whichtranslates to improved overall fatigue resistance.

It should further be appreciated that the homogenous (non-segmented)nature of the proposed screwdriver implicitly provides much higherangulation without sacrificing height/length to achieve. This is due toa very large extent to the superior elasticity of smart alloy materials.

Also, superior hygiene is realized compared to the segmented shaftapproach.

Most significantly, the present approach results in significantmanufacturing costs improvements over both the Straumann type design aswell as the Nobel Biocare design approach.

It should further be appreciated that a significant non-obvious effectof providing an arch-like bending section is that arches inherently havea natural starting point and a natural ending point. It is the spacebetween these points that curves to absorb non-radial forces in a mannerthat do not get passed along to the distal front end portion where thetorqueing affects must be singularly applied. This provides a unique andtremendous overall benefit in dental applications, but also in otherapplications where similar stresses exist.

Shaft and shaft tip specifications must allow for even and consistentshape transformation of the shaft, especially along the shaftbending-capable section, without the shaft exhibiting undue strain orkinking, and without distorting and/or adversely impacting the intendedmaximum desired torqueing force to be applied to a screw at the shafttip end. In other words, the shaft should bend and rotate where it issupposed to bend and rotate to match the curvature of the channel aboutwhich it is being rotated but without preventing an even maximumtorqueing force (measurable by a coupled torqueing tool) to be appliedto the tip end during tightening. To achieve this, constituent materialsfrom which the smart alloy is to be formed may need to be selected tomeet desired optimum use parameters.

Smart alloys are comprised of crystal nanostructures that makenon-destructive transformation possible. Further improvements may berealized by selecting tip ends and screw head dimensions that minimizenatural wear and tear of the smart alloy, and/or change kink-resistanceand stain deformation along the shaft. By altering the number of planesthat the screwdriver tip engages (for example, providing asixteen-faceted molecular structure), the smart alloy material fromwhich the screwdriver is manufactured may exhibit stronger molecularcompatibility resulting in increased resistance to breaking, wear or thelike at the point of contact with screw, allowing at the same timehardening the head only. In another scenario, and for similar reasons,the screw is also made of smart alloy material.

These and other features and advantages of the present invention will beapparent from the description of exemplary embodiments provided herein.

These and other features and advantages of the present invention will beapparent from the description of exemplary embodiments provided herein.

The embodiments described above are intended to illustrate aspects ofthe invention and modifications, variants and equivalents such as wouldbe readily apparent to the skilled person are encompassed within thescope of the invention such as defined, for example, by the claims.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the embodiments disclosed herein may be implemented aselectronic hardware, computer software, or combinations of both. Toclearly illustrate this interchangeability of hardware and software,various illustrative components, blocks, modules, circuits, and stepshave been described above generally in terms of their functionality.Whether such functionality is implemented as hardware or softwaredepends upon the particular application and design constraints imposedon the overall system. Skilled artisans may implement the describedfunctionality in varying ways for each particular application, but suchimplementation decisions should not be interpreted as causing adeparture from the scope of the exemplary embodiments of the invention.

In one or more exemplary embodiments, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosed exemplary embodiments isprovided to enable any person skilled in the art to make or use thepresent invention. Various modifications to these exemplary embodimentswill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other embodiments withoutdeparting from the spirit or scope of the invention. Thus, the presentinvention is not intended to be limited to the embodiments shown hereinbut is to be accorded the widest scope consistent with the principlesand novel features disclosed herein

What is claimed is:
 1. A shaft for a dental screwdriver configured to beinserted into a bore cavity of a dental prosthetic, the shaftcomprising: a drive tip for driving a dental screw used to fix thedental prosthetic to the dental implant when the shaft is inserted intothe bore cavity of the dental prosthetic, the drive tip being made of ashape memory smart alloy; and an axial shaft portion made of a shapememory smart alloy with different material characteristics than theshape memory smart alloy of the drive tip, the axial shaft portion beingconfigured to elastically bend from an original shape to a bent shapealong the axial shaft portion without imparting a bending action andtorqueing forces along the drive tip when the dental screwdriver isinserted into the bore cavity of the dental prosthetic.
 2. The shaft ofclaim 1, wherein the shape memory smart alloy of each of the axial shaftportion and the drive tip is nickel titanium alloy.
 3. The shaft ofclaim 1, wherein the axial shaft portion is formed in one piece with thedrive tip.
 4. The shaft of claim 1, wherein the axial shaft portion andthe drive tip are configured to travel through curved and straightspaces in the bore cavity of the dental prosthetic to reach the dentalscrew used to fix the dental prosthetic to the dental implant.
 5. Theshaft of claim 1, wherein the axial shaft portion is further configuredto elastically return to the original shape from the bent shape.
 6. Adental screwdriver having the shaft of claim
 1. 7. The dentalscrewdriver of claim 6, wherein the shape memory smart alloy of each ofthe axial shaft portion and the drive tip of the shaft is nickeltitanium alloy.
 8. A shaft for a dental screwdriver configured to beinserted into a bore cavity of a dental prosthetic, the shaftcomprising: a front end portion; a rear end portion opposite the frontend portion; an axial shaft portion made of a shape memory smart alloyand disposed between the front and rear end portions, the axial shaftportion being configured to elastically bend from an original shape to abent shape along the axial shaft portion without imparting a bendingaction and torqueing forces along the front and rear end portions whenthe dental screwdriver is inserted into the bore cavity of the dentalprosthetic; and a drive tip disposed at the front end portion fordriving a dental screw used to fix the dental prosthetic to a dentalimplant when the dental screwdriver is inserted into the bore cavity ofthe dental prosthetic, the drive tip being made of a shape memory smartalloy with different material characteristics than the shape memorysmart alloy of the axial shaft portion.
 9. The shaft of claim 8, whereinthe axial shaft portion is further configured to elastically return tothe original shape from the bent shape.
 10. The shaft of claim 9,wherein the shaft is configured such that a substantially linearcurvature is maintained near and along the front end portion when theaxial shaft portion elastically bends from the original shape to thebent shape and elastically returns towards the original shape from thebent shape to allow coupling of the drive tip to the dental screw whenthe shaft is inserted into the bore cavity of the dental prosthetic. 11.The shaft of claim 8, wherein the front end portion is less elastic thanthe axial shaft portion.
 12. The shaft of claim 8, wherein the axialshaft portion is formed in one piece with both the front end portion andthe drive tip.
 13. The shaft of claim 8, wherein the axial shaft portionand the drive tip are configured to travel through curved and straightspaces in the bore cavity of the dental prosthetic to reach the dentalscrew used to fix the dental prosthetic to the dental implant.
 14. Theshaft of claim 8, wherein the shape memory smart alloy of each of theaxial shaft portion and the drive tip is nickel titanium alloy.
 15. Adental screwdriver having the shaft of claim
 14. 16. A dentalscrewdriver having the shaft of claim 8.